Making z-fold multi-element substrate structure

ABSTRACT

A method of making a folded micro-wire substrate structure includes providing a transparent flexible substrate having a first side and a second side opposed to the first side. The flexible substrate has a first portion and a second portion adjacent to the first portion of the flexible substrate. One or more electrical conductors and one or more electrical components are formed on or in the flexible substrate. At least one optical element is formed on or in the flexible substrate in the second portion. The flexible substrate is folded with a first fold between the first and second portions so that the first portion is aligned with the second portion in a perpendicular direction and the optical element directs light to or from the electrical component.

CROSS REFERENCE TO RELATED APPLICATIONS

Reference is made to commonly-assigned, co-pending U.S. patentapplication Ser. No. 14/253,939, filed Apr. 16, 2014 entitled“Wrap-Around Micro-Wire Method” by Tombs et al, U.S. patent applicationSer. No. ______ (Kodak Docket K001781) filed concurrently herewith,entitled “Z-Fold Micro-Wire Substrate Structure” by Cok et al, tocommonly-assigned, co-pending U.S. patent application Ser. No. ______(Kodak Docket K001790) filed concurrently herewith, entitled “MakingZ-Fold Micro-Wire Substrate Structure” by Cok et al, and tocommonly-assigned, co-pending U.S. patent application Ser. No. ______(Kodak Docket K001791) filed concurrently herewith, entitled “Z-FoldMulti-Element Substrate Structure” by Cok et al, the disclosures ofwhich are incorporated herein.

FIELD OF THE INVENTION

The present invention relates to electrically conductive micro-wires,circuits, and optical elements formed on a common flexible substrate ina folded configuration.

BACKGROUND OF THE INVENTION

Electronic devices formed on flexible substrates are used inapplications that require non-planar forms or that require mechanicalmanipulation in different configurations. For example, some devices aredesigned to be folded or unfolded. Other devices are located on curvedsurfaces. A variety of technologies are under development for suchapplications, including organic electronics, inkjet deposition, polymerlayers, and flexible substrate materials such as polymers and paper.Such technologies enable applications such as flexible or curveddisplays, antennas, solar cells, batteries, sensors, and biomedicaldevices.

Flexible substrates or printed circuit boards are an important componentof flexible electronic devices. Currently, silk-screened metal wireconductors formed on a polymer substrate are used as flexible connectorsin many electronic systems. Such methods typically have limitedresolution. Other patterned conductors are formed usingphotolithographic processes on flexible materials, but such methods aretypically difficult because of material and process compatibility issuesand the expense of such processes. Such prior-art methods can alsoproduce devices with a relatively limited radius of curvature, therebylimiting the applications and configurations to which the technology isapplied.

There is also a need for high-density electronic devices thatincorporate three-dimensional circuit structures. Such structuresincrease the number of computing elements per volume but are typicallyexpensive to construct. Other applications integrate optical devicessuch as lenses or reflectors into optoelectronic devices. Such devicestypically include multiple, separate elements that are separatelymanufactured and then carefully aligned and integrated at a relativelyhigh resolution and cost.

Very fine patterns of conductive elements, such as metal wires orconductive traces are known. For example, U.S. Patent ApplicationPublication No. 2011/0007011 teaches a capacitive touch screen with amesh electrode, as do U.S. Patent Application Publication No.2010/0026664, U.S. Patent Application Publication No. 2010/0328248, andU.S. Pat. No. 8,179,381, which are hereby incorporated in their entiretyby reference. As disclosed in U.S. Pat. No. 8,179,381, fine conductorpatterns are made by one of several processes, including laser-curedmasking, inkjet printing, gravure printing, micro-replication, andmicro-contact printing. In particular, micro-replication is used to formmicro-conductors formed in micro-replicated channels. The transparentmicro-wire electrodes include micro-wires between 0.5μ and 4μ wide and atransparency of between approximately 86% and 96%.

Conductive micro-wires can be formed in micro-channels embossed in asubstrate, for example as taught in CN102063951, which is herebyincorporated by reference in its entirety. As discussed in CN102063951,a pattern of micro-channels is formed in a substrate using an embossingtechnique. Embossing methods are generally known in the prior art andtypically include coating a curable liquid, such as a polymer, onto arigid substrate. A pattern of micro-channels is imprinted (impressed orembossed) onto the polymer layer by a master having an inverted patternof structures formed on its surface. The polymer is then cured. Aconductive ink is coated over the substrate and into the micro-channels,the excess conductive ink between micro-channels is removed, for exampleby mechanical buffing, patterned chemical electrolysis, or patternedchemical corrosion. The conductive ink in the micro-channels is cured,for example by heating or exposure to HCl vapor. In an alternativemethod described in CN102063951, a photosensitive layer, chemicalplating, or sputtering is used to pattern conductors, for example, usingpatterned radiation exposure or physical masks. Unwanted material (e.g.photosensitive resist) is removed, followed by electro-deposition ofmetallic ions in a bath.

Multi-level masks are used with photo-lithography to form thin-filmdevices, for example as disclosed in U.S. Pat. No. 7,202,179. Animprinted 3D template structure is provided over multiple thin filmsformed on a substrate. The multiple levels of the template structure areused as masks for etching the thin films. This approach requires the useof a mask and multiple photo-lithographic steps.

The use of integrated circuits with electrical circuitry is well known.Various methods for providing integrated circuits on a substrate andelectrically connecting them are also known. Integrated circuits canhave a variety of sizes and packages. In one technique, Matsumura etal., in U.S. Patent Application Publication No. 2006/0055864, describescrystalline silicon substrates used for driving LCD displays. Theapplication describes a method for selectively transferring and affixingpixel-control devices made from first semiconductor substrates onto asecond planar display substrate. Wiring interconnections within thepixel-control device and connections from buses and control electrodesto the pixel-control device are shown.

Printed circuit boards are well known for electrically interconnectingintegrated circuits and often include multiple layers of conductors withvias for electrically connecting conductors in different layers. Circuitboards are often made by etching conductive layers deposited onlaminated fiberglass substrates. However, such etching processes areexpensive and the substrates are not transparent and therefore oflimited use in applications for which transparency is important, forexample display and touch-screen applications.

Flexible substrates are also known in the art and are used with otherdevices, such as displays. U.S. Pat. No. 6,501,528 discloses a stackeddisplay device with a folded substrate. U.S. Pat. No. 7,792,558describes a mobile communication device with bent connector wires andU.S. Pat. No. 8,017,884 illustrates an integrated touch panel andelectronic device. U.S. Pat. No. 5,520,112 describes a folded substrateand a dual-sided printing process. Such substrates, structures, andmethods demonstrate an on-going need in the industry for manufacturingmethods incorporating devices and flexible substrates.

SUMMARY OF THE INVENTION

There is a need, therefore, for further improvements in flexibleoptoelectronic devices that enable simplified manufacturing processesand fewer parts and processing steps at a lower cost.

In accordance with the present invention, a method of making a foldedmicro-wire substrate structure comprises:

providing a transparent flexible substrate having a first side and asecond side opposed to the first side, the flexible substrate having afirst portion and a second portion adjacent to the first portion of theflexible substrate;

forming one or more electrical conductors and one or more electricalcomponents on or in the flexible substrate;

forming at least one optical element on or in the flexible substrate inthe second portion; and

folding the flexible substrate with a first fold between the first andsecond portions so that the first portion is aligned with the secondportion in a direction perpendicular to the first and second portions ofthe flexible substrate and the optical element directs light to or fromthe electrical component.

The present invention provides micro-wire structures in flexibleconfigurations having improved electrical connectivity, processingcapability, optical attributes and capabilities, and manufacturability.The micro-wire structures of the present invention are particularlyuseful in display devices or systems or photovoltaic devices or systems.The integration of active electronic devices, electrical conductors, andoptical elements on a single flexible substrate reduces the number ofparts, for example fewer electrical connectors are needed and permitsfewer manufacturing steps, thereby reducing costs.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present inventionwill become more apparent when taken in conjunction with the followingdescription and drawings wherein identical reference numerals have beenused to designate identical features that are common to the figures, andwherein:

FIG. 1A is a cross section of an embodiment of the present invention ina folded configuration;

FIG. 1B is a cross section of an embodiment of the present inventioncorresponding to FIG. 1A in a flat, unfolded configuration;

FIG. 1C is a plan view of an embodiment of the present invention in aflat, unfolded configuration having a cross section line correspondingto the embodiments of FIGS. 1A and 1B;

FIG. 2A is a cross section of an embodiment of the present invention ina folded configuration;

FIG. 2B is a cross section of an embodiment of the present inventioncorresponding to FIG. 2A in a flat, unfolded configuration;

FIG. 3A is a cross section of an embodiment of the present invention ina folded configuration;

FIG. 3B is a cross section of an embodiment of the present inventioncorresponding to FIG. 3A in a flat, unfolded configuration;

FIG. 4A is a cross section of an embodiment of the present invention ina folded configuration;

FIG. 4B is a cross section of an embodiment of the present inventioncorresponding to FIG. 4A in a flat, unfolded configuration;

FIG. 5A is a cross section of an embodiment of the present invention ina folded configuration;

FIG. 5B is a cross section of an embodiment of the present inventioncorresponding to FIG. 5A in a flat, unfolded configuration;

FIGS. 6-10 are partial cross sections of embodiments of the presentinvention;

FIGS. 11-12 are flow diagrams illustrating various methods of thepresent invention;

FIGS. 13-14 are schematics illustrating various methods of the presentinvention; and

FIG. 15 is a flow diagram illustrating a method of the presentinvention.

The Figures are not drawn to scale since the variation in size ofvarious elements in the Figures is too great to permit depiction toscale.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed toward a folded micro-wire circuitstructure that can incorporate aligned optical, conductive, andprocessing elements. The present invention is usefully constructed witha single substrate and methods of the present invention can formelectrical and optical structures in common steps with common tools toreduce construction costs.

FIG. 1A illustrates a folded embodiment of the present invention, FIG.1B illustrates a flat, unfolded embodiment of the present invention, andFIG. 1C is a plan view of a flat, unfolded embodiment of the presentinvention. The cross sections of FIGS. 1A and 1B are taken across crosssection line A of FIG. 1C. Referring to FIGS. 1A, 1B, and 1C, in anembodiment of the present invention, a folded micro-wire substratestructure 5 includes a folded flexible substrate 10 having a first side12 and a second side 14 opposed to the first side 12 in a direction 40perpendicular to the first side 12. The flexible substrate 10 has afirst portion 21, a second portion 22 adjacent to the first portion 21,and a third portion 23 adjacent to the second portion 22 so that thesecond portion 22 is between the first portion 21 and the third portion23 of the flexible substrate 10 in a substrate direction 42 of theflexible substrate 10 when the flexible substrate 10 is in a flat,unfolded configuration (FIG. 1B). The perpendicular direction 40 is alsoperpendicular to the first, second, and third portions 21, 22, 23 in theflat, unfolded configuration (FIG. 1B).

In a folded configuration (FIG. 1A), the substrate direction 42 is alongthe surface of the flexible substrate 10. In the folded configuration ofFIG. 1A, the flexible substrate 10 has at least a first fold 31 betweenthe first and second portions 21, 22 so that the first portion 21 isalso adjacent to the second portion 22 in the perpendicular direction40. The flexible substrate 10 has at least a second fold 32 between thesecond and third portions 22, 23 so that the second side 14 is alsobetween the second and third portions 22, 23 in the perpendiculardirection 40. One or more electrical conductors 50 are located in or onthe flexible substrate 10.

In various embodiments, the flexible substrate 10 is or includes apolymer material or layers including polymers. The electrical conductors50 are metal, are formed from sintered or agglomerated metal particles,are located on the surface of the flexible substrate 10, or are locatedin micro-channels formed in the surface of the flexible substrate 10 andextending into the flexible substrate 10. Such materials are known inthe art. In a useful embodiment, the electrical conductors 50 aremicro-wires and the electrical conductors 50 are considered to bemicro-wires and are also referred to as micro-wire herein.

In the folded configuration of FIG. 1A, the first and second folds 31,32 fold the flexible substrate 10 into a stacked or foldedconfiguration. In the flat configuration of FIGS. 1B and 1C, the first,second, and third portions 21, 22, 23 are located substantially in aplane. In this configuration, the first fold 31 separates the first andsecond portions 21, 22 in a direction parallel to the substratedirection 42 or along the flexible substrate 10 and the second fold 32separates the second and third portions 22, 23 in a direction parallelto the substrate direction 42 or along the flexible substrate 10. In theflat configuration, the first and second folds 31, 32 are not folded andare also referred to herein as the first and second fold gaps 31, 32since they separate the different portions of the flexible substrate 10substantially in a plane.

As used herein, portions are adjacent when two portions do not haveanother portion between them. Two portions can be adjacent in thesubstrate direction 42 or along the flexible substrate 10, for examplewhen the flexible substrate 10 is in a flat configuration. Two portionscan be adjacent in the perpendicular direction 40 when there is no otherportion between them when the flexible substrate 10 is in the foldedconfiguration. Thus, in FIG. 1A, the first portion 21 is adjacent to thesecond portion 22 and the second portion 22 is adjacent to the thirdportion 23 in the perpendicular direction 40. The first portion 21 isnot adjacent to the third portion 23 in the perpendicular direction 40because the second portion 22 is between the first and third portions21, 23 in the perpendicular direction 40. Similarly, in FIGS. 1B and 1C,the first portion 21 is adjacent to the second portion 22 and the secondportion 22 is adjacent to the third portion 23 in the substratedirection 42. The first portion 21 is not adjacent to the third portion23 in the substrate direction 42 because the second portion 22 isbetween the first and third portions 21, 23 in the substrate direction42. In the folded configuration of FIG. 1A, the first portion 21 isadjacent to the second portion 22 in both the perpendicular direction 40and along the surface or first side 12 of the flexible substrate 10.Similarly, the second portion 22 is adjacent to the third portion 23 inboth the perpendicular direction 40 and along the surface or first side12 of the flexible substrate 10.

In a further embodiment of the present invention, the folded micro-wiresubstrate structure 5 further includes at least one electrical component60 on or in the flexible substrate 10 in the first, second, or thirdportion 21, 22, 23. In an embodiment, the electrical component 60 is anactive component, such as an organic transistor or an inorganictransistor. The electrical component 60 can use the same substrate asthe flexible substrate 10 or have a substrate different from theflexible substrate 10, for example the electrical component 60 is anintegrated circuit having an inflexible semiconductor substrate such assilicon completely different from but affixed to the flexible substrate10. Alternatively, the electrical component 60 is an integrated circuitformed directly on or in the flexible substrate 10.

In various embodiments, the electrical component 60 forms an electricalcircuit, is a part of an electrical circuit, or multiple electricalcomponents 60 are electrically connected with electrical conductors 50to form a circuit. In an arrangement, the electrical components 60 arelocated on both the first and second portions 21, 22. The electricalcomponents 60 can process information, receive or transmit signals, orform a power circuit. In an embodiment, the electrical components 60 arelight-interactive electrical components 62 that absorb light or otherelectro-magnetic radiation to produce electrical power, such as current,for example in a photo-voltaic system. Alternatively, the electricalcomponents 60 are light-interactive electrical components 62 that emitlight or other electro-magnetic radiation in response to electricalpower, current, or voltage, for example in a display system. In a usefularrangement, the light-interactive electrical components 62 are locatedin the second portion 22 and the electrical components 60 are located inthe first portion 21. The light-interactive electrical components 62 inthe second portion 22 are electrically connected to the electricalcomponents 60 in the first portion 21 with electrical conductors 50 thatextend from the first portion 21, through the first fold 31, into thesecond portion 22. Thus, in an embodiment, at least one electricalconductor 50 extends from the first portion 21 to the second portion 22and across the first fold 31, at least one electrical conductor 50extends from the second portion 22 to the third portion 23 and acrossthe second fold 32, or at least one electrical conductor 50 extends fromthe first portion 21 to the third portion 23 and across the first andsecond folds 31, 32 (not shown).

In another embodiment of the folded micro-wire substrate structure 5,the flexible substrate 10 is at least partially transparent and furtherincludes one or more optical elements 70 on or in the flexible substrate10 in the first, second, or third portions 21, 22, 23. In variousembodiments, the optical elements 70 serve to redirect light 44, forexample with refraction or reflection. In a useful embodiment, theoptical elements 70 are lenses, for example convex or concave lenses.

In a useful embodiment, the first and second folds 31, 32, the opticalelements 70, and the electrical components 60 or light-interactiveelectrical components 62 are aligned on the flexible substrate 10 sothat at least one electrical component 60 or light-interactiveelectrical component 62 on or in the flexible substrate 10 in the first,second, or third portions 21, 22, or 23 is located so that light 44 isdirected through the optical elements 70 to or from the electricalcomponents 60 or light-interactive electrical components 62. In a usefularrangement, the electrical component 60 is located in the first portion21, the light-interactive electrical component 62 is located in thesecond portion 22, and the optical element 70 is in the third portion 23and the light travels through the flexible substrate 10. In variousembodiments, the optical element 70 is formed in the flexible substrate10 or secured to the flexible substrate 10, for example mechanically orwith an adhesive. The flexible substrate 10 is substantiallytransparent, for example more than 50%, more than 70%, more than 80%,more than 90%, or more than 95% transparent to visible light or otherelectro-magnetic radiation.

In an alternative embodiment of the present invention, the foldedmicro-wire substrate structure 5 includes the folded flexible substrate10 having the first side 12 and the second side 14 opposed to the firstside 12 in the direction 40 perpendicular to the first side 12. Theflexible substrate 10 has the first portion 21, the second portion 22adjacent to the first portion 21, and the third portion 23 adjacent tothe second portion 22 so that the second portion 22 is between the firstand third portions 21, 23 of the flexible substrate 10 in the substratedirection 42 in a flat configuration. The first portion 21 is separatedfrom the second portion 22 by the first fold gap 31 and the secondportion 22 is separated from the third portion 23 by the second fold gap32 along the flexible substrate 10. One or more electrical conductors 50are located in or on the flexible substrate 10 and extend from the firstportion 21 into the second portion 22 across the first fold gap 31. Thethird portion 23 includes at least one optical element 70 on or in theflexible substrate 10. In a further embodiment, the folded micro-wiresubstrate structure 5 includes one or more electrical components 60electrically connected to the one or more electrical conductors 50 inthe first or second portions 21, 22.

Referring next to FIGS. 2A and 2B, in another embodiment of the presentinvention, the folded micro-wire substrate structure 5 includes theflexible substrate 10 having the first side 12 and the second side 14opposed to the first side 12 in the direction 40 perpendicular to thefirst side 12. The flexible substrate 10 has the first portion 21 andthe second portion 22 adjacent to the first portion 21 of the flexiblesubstrate 10 in the substrate direction 42 when the flexible substrate10 is in a flat, unfolded configuration (FIG. 2B). The flexiblesubstrate 10 has at least the first fold 31 between the first and secondportions 21, 22 so that the first portion 21 is aligned and adjacentwith the second portion 22 in the perpendicular direction 40 (FIG. 2A).One or more electrical conductors 50 are located in or on the flexiblesubstrate 10. At least one electrical component 60 or light-interactiveelectrical component 62 is located on or in the flexible substrate 10 inthe first portion 21. At least one optical element 70 is located on orin the flexible substrate 10 in the second portion 22 so that theoptical element 70 directs light 44 to or from the electrical component60 or the light-interactive electrical component 62. In an embodiment anextended portion 26 of the flexible substrate 10 adjacent to the firstportion 21 extends beyond the second portion 22 in the substratedirection 42 in the folded configuration.

In a further embodiment, the folded micro-wire substrate structure 5includes the flexible substrate 10 having the first side 12 and thesecond side 14 opposed to the first side 12 in the direction 40perpendicular to the first side 12. The flexible substrate 10 has thefirst portion 21 and the second portion 22 adjacent to the first portion21 of the flexible substrate 10. The flexible substrate 10 has at leastthe first fold gap 31 between the first and second portions 21 22. Oneor more electrical conductors 50 is located in or on the flexiblesubstrate 10 in the first portion 21 and at least one optical element 70is located on or in the flexible substrate 10 in the second portion 22.In a further embodiment, the folded micro-wire substrate structure 5further includes at least one electrical component 60 orlight-interactive electrical component 62 on or in the flexiblesubstrate 10 in the first portion 21 electrically connected to one ormore of the electrical conductors 50.

In the embodiment of FIGS. 1A, 1B, and 1C and the embodiment of FIGS. 2Aand 2B, the electrical conductors 50, the light-interactive electricalcomponents 62, and the optical elements 70 are all located on the firstside 12 of the flexible substrate 10. Referring next to FIGS. 3A and 3B,in another embodiment of the present invention, the folded micro-wiresubstrate structure 5 includes the flexible substrate 10 having thefirst side 12 and the second side 14 opposed to the first side 12 in thedirection 40 perpendicular to the first side 12. The flexible substrate10 has the first portion 21 and the second portion 22 adjacent to thefirst portion 21 of the flexible substrate 10 in the substrate direction42 when the flexible substrate 10 is in a flat, unfolded configuration(FIG. 3B). The flexible substrate 10 has at least the first fold 31between the first and second portions 21, 22 so that the first portion21 is aligned and adjacent to the second portion 22 in the perpendiculardirection 40 (FIG. 3A). One or more electrical conductors 50 are locatedin or on the flexible substrate 10. At least one electrical component 60or light-interactive electrical component 62 is located on or in theflexible substrate 10 in the first portion 21. At least one opticalelement 70 is located on or in the flexible substrate 10 in the secondportion 22 on a side of the flexible substrate 10 opposite a side of theflexible substrate 10 than has the electrical component 60 orlight-interactive electrical component 62 located thereon so that theoptical element 70 directs light 44 to or from the electrical component60 or the light-interactive electrical component 62. In an embodimentthe extended portion 26 of the flexible substrate 10 adjacent to thefirst portion 21 extends beyond second portion 22 in the substratedirection 42 in the folded configuration.

Turning next to FIGS. 4A and 4B, the folded micro-wire substratestructure 5 includes the flexible substrate 10 having the first side 12and the second side 14 opposed to the first side 12 in the direction 40perpendicular to the first side 12. The flexible substrate 10 has thefirst portion 21 and the second portion 22 adjacent to the first portion21 of the flexible substrate 10 in the substrate direction 42 when theflexible substrate 10 is in a flat, unfolded configuration (FIG. 4B).The flexible substrate 10 has at least the first fold 31 between thefirst and second portions 21, 22 so that the first portion 21 is alignedand adjacent to the second portion 22 in the perpendicular direction 40(FIG. 4A). The flexible substrate 10 further includes a fourth portion24 adjacent to the third portion 23 so that the third portion 23 isbetween the second and fourth portions 22, 24 of the flexible substrate10, both on the first side 12 along the surface of the flexiblesubstrate 10 in the substrate direction 42 and in the perpendiculardirection 40. The flexible substrate 10 has a third fold 33 between thethird and fourth portions 23, 24 so that the fourth portion 24 isadjacent to the third portion 23 in the perpendicular direction 40.

Similarly, referring to FIGS. 5A and 5B, the folded micro-wire substratestructure 5 includes the flexible substrate 10 having the first side 12and the second side 14 opposed to the first side 12 in the direction 40perpendicular to the first side 12. The flexible substrate 10 has thefirst portion 21 and the second portion 22 adjacent to the first portion21 of the flexible substrate 10 in the substrate direction 42 when theflexible substrate 10 is in a flat, unfolded configuration (FIG. 4B).The flexible substrate 10 has at least the first fold 31 between thefirst and second portions 21, 22 so that the first portion 21 is alignedand adjacent to the second portion 22 in the perpendicular direction 40(FIG. 4A). The flexible substrate 10 includes the fourth portion 24adjacent to the third portion 23 so that the third portion 23 is betweenthe second and fourth portions 22, 24 of the flexible substrate 10, bothon the first side 12 along the surface of the flexible substrate 10 inthe substrate direction 42 and in the perpendicular direction 40. Theflexible substrate 10 has the third fold 33 between the third and fourthportions 23, 24 so that the fourth portion 24 is adjacent to the thirdportion 23 in the perpendicular direction 40. The flexible substrate 10further includes a fifth portion 25 adjacent to the fourth portion 24 sothat the fourth portion 24 is between the third and fifth portions 23,25 of the flexible substrate 10, both on the first side 12 along thesurface of the flexible substrate 10 in the substrate direction 42 andin the perpendicular direction 40. The flexible substrate 10 has afourth fold 34 between the fourth and fifth portions 24, 25 so that thefifth portion 25 is adjacent to the fourth portion 24 in theperpendicular direction 40.

Referring next to FIGS. 6 and 7, the optical element 70 is a firstoptical element 70 on or in the first side 12 and the flexible substrate10 further includes at least one second optical element 72 on or in thesecond side 14. In one embodiment, as shown in FIG. 6, the first andsecond optical elements 70, 72 have a common optical axis 74. In anotherembodiment, as shown in FIG. 7, the first and second optical elements70, 72 do not have a common optical axis 74. As noted with respect toFIG. 1A, the first and second optical elements 70, 72 are effective todirect light to the light-sensitive electrical components (not shown inFIGS. 6 and 7).

Referring next to FIGS. 8 and 9, in an embodiment of the presentinvention, the folded micro-wire substrate structure 5 further includesan additional substrate 16 located between the first and second portions21, 22 or between the second and third portions 22, 23 of the flexiblesubstrate 10 in the perpendicular direction 40. In one embodiment, theadditional substrate 16 is electrically insulating. In anotherembodiment, the additional substrate 16 is transparent. Referringspecifically to FIG. 9 in yet another embodiment, the additionalsubstrate 16 has one or more optical elements 70 formed in or secured tothe additional substrate 16. The optical elements 70 are located on oneside of the additional substrate 16 or on both sides, as shown in FIG.9.

In a further embodiment of the present invention illustrated in FIG. 10,the folded micro-wire substrate structure 5 further includes aprotective layer 18 on the flexible substrate 10 so that at least oneelectrical conductor 50 is between the protective layer 18 and at leasta portion of the flexible substrate 10. The protective layer 18 caninclude a polymer or layers of polymers and, in an embodiment is curedand includes, for example cross linking materials. In a usefulembodiment, the protective layer 18 is transparent.

The protective layer 18 can protect the flexible substrate 10, theelectrical conductors 50, or the electrical components 60 fromenvironmental damage. In an embodiment, the protective layer 18 relievesstress or strain on the electrical conductors 50 when the flexiblesubstrate 10 and portions of the electrical conductors 50, for examplein the first or second folds 31 or 32 are in a folded configuration. Inan embodiment, the electrical conductors 50 have a thickness less thanone half the thickness of the flexible substrate 10. In anotherembodiment, the protective layer 18 has a thickness equal to, or greaterthan, the flexible substrate (not shown).

As shown in FIGS. 2A, 2B, 3A, 3B, and 10, in an embodiment the flexiblesubstrate 10 further includes the extended portion 26 adjacent to thefirst portion 21 so that the first portion 21 is located between theextended portion 26 and the second portion 22 in the substrate direction42 and so that there is no portion of the flexible substrate 10 adjacentto the extended portion 26 in the perpendicular direction 40. Theextended portion 26 is useful for connecting an external device, such asan electronic controller or other electrical component, to theelectrical conductors 50, for example with a wire 54 or ribbon cableincluding a plurality of wires 54, each connected to a differentelectrical conductor 50. The electrical conductor 50 can form aconnection pad to which the wire 54 is affixed. Wires 54, ribbon cables,and electronic controllers are known in the art.

In a further embodiment of the present invention, as shown in FIG. 10,the folded micro-wire substrate structure 5 further includes anelectrical connector 52 between an electrical conductor 50 or electricalcomponent 60 in the first portion 21 and an electrical conductor 50 orelectrical component 60 in the second portion 22 that does not extendacross the first fold 31. Such an electrical connector 52 can directlyconnect electrical conductors 50 or electrical components 60 from oneportion of the flexible substrate 10 to another portion and provideconnectivity to the electrical circuit formed by the electricalconductors 50 and electrical components 60.

In yet another embodiment, at least a part of the first portion 21 is incontact with at least a part of the second portion 22, or at least apart of the second portion 22 is in contact with at least a part of thethird portion 23. Contacting the portions can aid in manufacturingalignment, forming electrical connections between electrical conductors50 in different portions, or in light transmission. Such a contact canalso seal the various components to prevent exposure to the ambientenvironment. In an embodiment, a patterned insulating adhesive orUV-curable layer is put between at least part of the portions to assistin adhesion and contacting only those desired parts of the portions. Inone embodiment, the additional substrate 16 (FIG. 8) is patterned sothat at least some parts of the first, second, or third portions 21, 22,23 are in contact.

The present invention provides a structure and method for making ahigh-density electronic or optoelectronic circuit on a single flexiblesubstrate 10. The structure can form a three-dimensional circuit and isuseful for a variety of applications, including photo-voltaic systemsfor generating electrical power from electromagnetic energy (e.g. solarpower) or for light-emitting systems such as displays. Because thehigh-density electronic or optoelectronic circuit is formed on a singleflexible substrate 10, manufacturing process costs are reduced, partscount is reduced, and alignment simplified. Moreover, in an embodimentthe folded micro-wire substrate structure 5 is manufactured in a flatconfiguration and then folded when in operation. Furthermore, in anembodiment, the folded micro-wire substrate structure 5 is unfolded intoa flat configuration after operation in a folded configuration. In otheruseful processes, the micro-wire substrate structure is transported in aflat configuration.

Referring to FIG. 11, a method of making the folded micro-wire substratestructure 5 includes providing the flexible substrate 10 having thefirst side 12 and the second side 14 opposed to the first side 12 in thedirection 40 perpendicular to the first side 12 in step 100. Theflexible substrate 10 has the first portion 21, the second portion 22adjacent to the first portion 21, and the third portion 23 adjacent tothe second portion 22 so that the second portion 22 is located betweenthe first and third portions 21, 23 of the flexible substrate 10 in thesubstrate direction 42.

In optional step 110, a surface (e.g. first side 12) of the flexiblesubstrate 10 is structured to form micro-channels and one or moreoptical elements 70. In an embodiment, the formation of themicro-channels and the optical elements 70 is done at least partly in asingle processing step with common materials. One or more electricalconductors 50 are formed on or in the flexible substrate 10 in step 110,for example in the micro-channels or printed on the first side 12. Inoptional step 120, the electrical components 60 are located on theflexible substrate 10 in electrical communication with the electricalconductors 50. In another optional step 130, the protective layer 18 iscoated on the flexible substrate 10. The protective layer 18 can coverthe electrical conductors 50 or the electrical components 60. Anexternal electrical connection, for example a ribbon cable includingwires 54 is electrically connected to one or more of the electricalconductors 50 in step 140. In optional step 150, the flexible substrate10 is inspected for flaws. In various embodiments, one or moreinspection steps 150 are performed after the various different steps ofthe method.

The flexible substrate 10 is folded in step 160 with the first fold 31between the first and second portions 21, 22 so that the first portion21 is located adjacent to the second portion 22 in the perpendiculardirection 40 and with at least the second fold 32 between the second andthird portions 22, 23 so that the second side 14 is between the secondportion 22 and the third portion 23 in the perpendicular direction 40.In step 170, the folded flexible substrate 10 is secured to form thefolded micro-wire substrate structure 5. In one embodiment, when in afolded configuration the different portions are secured to each otherwith adhesives. In another embodiment, a mechanical structure isprovided.

In another embodiment of the present invention, a method of making thefolded micro-wire substrate structure 5 includes providing the flexiblesubstrate 10 having the first side 12 and the second side 14 opposed tothe first side 12 in the direction 40 perpendicular to the first side 12in step 100. The flexible substrate 10 has the first portion 21, thesecond portion 22 adjacent to the first portion 21, and the thirdportion 23 adjacent to the second portion 22 so that the second portion22 is located between the first and third portions 21, 23 of theflexible substrate 10 in the substrate direction 42. The first portion21 is separated from the second portion 22 by the first fold gap 31 andthe second portion 22 is separated from the third portion 23 by thesecond fold gap 32. One or more optical elements 70 are formed on or inthe flexible substrate 10 in the third portion 23 in step 110 or one ormore electrical conductors 50 are formed in step 110 on or in theflexible substrate 10 in the first or second portions 21, 22 extendingfrom the first portion 21 into the second portion 22 across the firstfold gap 31. In a further embodiment, a method of the present inventionfurther includes forming one or more electrical components 60 on theflexible substrate 10 electrically connected to the one or moreelectrical conductors 50 in the first or second portions 21, 22 in step120.

In yet another embodiment, a method of making the folded micro-wiresubstrate structure 5 includes providing a transparent flexiblesubstrate 10 having the first side 12 and the second side 14 opposed tothe first side 12 in the direction 40 perpendicular to the first side 12in step 100. The flexible substrate 10 has the first portion 21 and thesecond portion 22 adjacent to the first portion 21 of the flexiblesubstrate 10. One or more optical elements 70 are formed in step 110 onor in the flexible substrate 10 in the second portion 22, one or moreelectrical conductors 50 are formed in step 110 on or in the flexiblesubstrate 10, and one or more electrical components 60 are formed instep 120 on or in the flexible substrate 10. The flexible substrate 10is folded in step 160 with the first fold 31 between the first andsecond portions 21, 22 so that the first portion 21 is aligned with thesecond portion 22 in the perpendicular direction 40 and the opticalelement 70 directs light 44 to or from the electrical component 60.

In a further embodiment, a method of making the folded micro-wiresubstrate structure 5 includes providing the transparent flexiblesubstrate 10 having the first side 12 and the second side 14 opposed tothe first side 12 in the direction 40 perpendicular to the first side 12in step 100. The flexible substrate 10 has the first portion 21 and thesecond portion 22 adjacent to the first portion 21 of the flexiblesubstrate 10 and is separated from the first portion 21 by the firstfold gap 31. One or more optical elements 70 is formed on or in theflexible substrate 10 in the second portion 22 and one or moreelectrical conductors 50 is formed on or in the flexible substrate 10 inthe first portion 21.

In embodiments, the flexible substrate 10 is any substrate that is bentor folded at least once and that has a surface on which the electricalconductors 50, electrical components 60, or optical elements 70 areformed. In an embodiment, the flexible substrate 10 is a plastic orpolymer material, is transparent, and has opposing substantiallyparallel and extensive surfaces (e.g. first side 12 and second side 14),or additional layers. In various embodiments, the flexible substrate 10is transparent, for example transmitting 50%, 80%, 90%, 95% or more ofvisible light. The flexible substrates 10 can include a dielectricmaterial and can have a wide variety of thicknesses, for example 10microns, 50 microns, 100 microns, 1 mm, or more.

In an embodiment, the electrical conductors 50 are micro-wires inmicro-channels in the flexible substrate 10 or the electrical components60 are printed on the flexible substrate 10, for example by gravureprinting, offset printing, flexographic printing, or inkjet printing. Ina useful method, a patterned stamp or printing plate is provided andcoated with a conductive ink, and the conductive ink is printed on thefirst side 12, the second side 14, or both the first and second sides12, 14 of the flexible substrate 10. In another embodiment, theconductive ink is printed with an inkjet printer. Alternatively, theelectrical conductors 50 or electrical components 60 are affixed to theflexible substrate 10. For example, pick-and-place technologies foraffixing integrated circuits to a substrate are well known. In oneembodiment, the electrical components 60 are located on the flexiblesubstrate 10 or formed on the flexible substrate 10 after the electricalconductors 50 are located on the flexible substrate 10 or formed on theflexible substrate 10. Alternatively, the electrical components 60 arelocated on the flexible substrate 10 or formed on the flexible substrate10 before the electrical conductors 50 are located on the flexiblesubstrate 10 or formed on the flexible substrate 10. The electricalcomponents 60 can include pads or leads that are soldered or otherwiseelectrically connected to the electrical conductors 50 using methodsknown in the art, for example with anisotropic conductive films.

In various embodiments, the electrical components 60 are integratedcircuits using inorganic materials that are placed and affixed to theflexible substrate 10. In other embodiments, the electrical components60 are formed on the flexible substrate 10, for example using organicmaterials known in the art such as pentacene or using inorganicmaterials. Methods including coating, curing, and patterning materialsare usable and known in the art, for example using photolithographictechniques or atomic layer deposition and selective area depositionmethods.

Referring next to FIG. 12, in a useful embodiment, the flexiblesubstrate 10 includes a layer on a side of a support and a method of thepresent invention further includes coating a curable layer on the sideof the support in step 111. The curable layer can be a polymer or resinlayer that includes cross linking elements activated by heat orradiation to form a cured layer. The coated curable layer is imprintedin step 112, for example with a stamp, to form micro-channels for theelectrical conductors 50 or to form optical elements 70. The curablelayer is cured in step 113 to form a cured layer having themicro-channels or optical elements 70, for example using heat orradiation. The cured layer forms the layer on the side of the supportand a surface of the cured layer is opposite the support forming thefirst side 12. Steps 111 through 113 effectively structure the surfaceof the flexible substrate 10 in step 110.

Imprinted structures are also known to those skilled in the art asembossed or impressed structures formed by locating in a curable layeran imprinting, impressing, or embossing stamp having protrudingstructural features, curing the layer, and then removing the stamp toform micro-channels or optical elements 70 corresponding to thestructural features.

In various embodiments, curable layers are deposited as a single layerin a single step using coating methods known in the art, e.g. curtaincoating. In an alternative embodiment, curable layers are deposited asmultiple sub-layers using multi-level deposition methods known in theart, e.g. multi-level slot coating, repeated curtain coatings, ormulti-level extrusion coating. In yet another embodiment, curable layersinclude multiple sub-layers formed in different, separate steps, forexample with a multi-level extrusion, curtain coating, or slot coatingas is known in the coating arts. Such coating methods are alsoapplicable to forming the protective layer 18.

Cured layers useful in the present invention can include a cured polymermaterial with cross-linking agents that are sensitive to heat orradiation, for example infra-red, visible light, or ultra-violetradiation. The polymer material can be a curable material applied in aliquid form that hardens when the cross-linking agents are activated,for example with exposure to radiation or heat. Micro-channels andoptical elements 70 are embossed and cured in curable layers in a singlestep using a single stamp that includes structural elements for formingboth micro-channels and lens structures. When a molding device, such asa stamp having an inverse micro-channel or optical element 70 structureis applied to liquid curable material in a curable layer coated on theflexible substrate 10 and the cross-linking agents in the curablematerial are activated, the liquid curable material in the curable layeris hardened into a cured layer having micro-channels or optical element70 or both with the inverse structure of the stamp. Thus, in anembodiment, a method of the present invention includes imprinting one ormore optical elements 70 in the curable layer in a common step withimprinting the micro-channels. The liquid curable materials can includea surfactant to assist in controlling coating. Materials, tools, andmethods are known for embossing coated liquid curable materials to formcured layers having conventional single-layer micro-channels.

Referring next to step 114 of FIG. 12, a method of the present inventionfurther includes coating the cured layer and micro-channels with aconductive ink. Excess conductive ink is removed from the surface of thecured layer in step 115 and the conductive ink in the micro-channels iscured in step 116, for example using heat, HCl vapor, or radiation, toform micro-wires in the micro-channels that are the electricalconductors 50.

Curable inks useful in the present invention are known and can includeconductive inks having electrically conductive nano-particles, such assilver nano-particles. The electrically conductive nano-particles can bemetallic or have an electrically conductive shell. In variousembodiments, the electrically conductive nano-particles are silver, area silver alloy, include silver, are copper, are a copper alloy, orinclude copper. In other embodiments, cured inks can include metalparticles, for example nano-particles. The metal particles can besintered to form a metallic electrical conductor. The metalnano-particles can be silver or a silver alloy or other metals, such astin, tantalum, titanium, gold, copper, or aluminum, or alloys thereof.Cured inks can include light-absorbing materials such as carbon black, adye, or a pigment.

Curable inks provided in a liquid form are deposited or located inmicro-channels and cured, for example by heating or exposure toradiation such as infra-red, visible light, or ultra-violet radiation.The curable ink hardens to form the cured ink that makes up micro-wiresuseful as electrical conductors 50. For example, a curable conductiveink with conductive nano-particles is located within micro-channels andheated to agglomerate or sinter the nano-particles, thereby forming anelectrically conductive micro-wire. Materials, tools, and methods areknown for coating liquid curable inks to form the micro-wires inconventional single-layer micro-channels. The curable conductive ink isnot necessarily electrically conductive before it is cured.

Electrically conductive micro-wires and methods of the present inventionare useful for making electrical conductors 50, for example as used inelectrodes and electrical buses. A variety of micro-wire ormicro-channel patterns can be used and the present invention is notlimited to any one pattern. The micro-wires can be spaced apart, formseparate electrical conductors 50, or intersect to form a meshelectrical conductor on or in a layer. Micro-channels can be identicalor have different sizes, aspect ratios, or shapes. Similarly, themicro-wires can be identical or have different sizes, aspect ratios, orshapes. Micro-wires can be straight or curved.

In some embodiments, a micro-channel is a groove, trench, or channelformed in a cured layer and having a cross-sectional width less than 20microns, for example 10 microns, 5 microns, 4 microns, 3 microns, 2microns, 1 micron, or 0.5 microns, or less. In an embodiment, amicro-channel depth is comparable to a micro-channel width.Micro-channels can have a rectangular cross section. Othercross-sectional shapes, for example trapezoids, are known and areincluded in the present invention. The width or depth of a layer ismeasured in cross section.

In an embodiment, a curable ink can include conductive nano-particles ina liquid carrier (for example an aqueous solution including surfactantsthat reduce flocculation of metal particles, humectants, thickeners,adhesives or other active chemicals). The liquid carrier can be locatedin micro-channels and heated or dried to remove liquid carrier ortreated with hydrochloric acid, leaving a porous assemblage ofconductive particles that can be agglomerated or sintered to form aporous electrical conductor in a layer. Thus, in an embodiment, curableinks are processed to change their material compositions, for exampleconductive particles in a liquid carrier are not electrically conductivebut after processing form an assemblage that is electrically conductive.

Once deposited, the conductive inks are cured, for example by heating.The curing process drives out the liquid carrier and sinters the metalparticles to form a metallic electrical conductor. Conductive inks areknown in the art and are commercially available. In any of these cases,conductive inks or other conducting materials are conductive after theyare cured and any needed processing completed. Deposited materials arenot necessarily electrically conductive before patterning or beforecuring. As used herein, a conductive ink is a material that iselectrically conductive after any final processing is completed and theconductive ink is not necessarily conductive at any other point in themicro-wire formation process.

In an example and non-limiting embodiment of the present invention, eachmicro-wire is from 10 to 15 microns wide, from 5 to 10 microns wide,from one micron to five microns wide or from one/half micron to onemicron wide. In some embodiments, micro-wires can fill micro-channels;in other embodiments micro-wires do not fill micro-channels. In anembodiment, micro-wires are solid; in another embodiment micro-wires areporous.

Micro-wires can include metal, for example silver, gold, aluminum,nickel, tungsten, titanium, tin, or copper or various metal alloysincluding, for example silver, gold, aluminum, nickel, tungsten,titanium, tin, or copper. Micro-wires can include a thin metal layercomposed of highly conductive metals such as gold, silver, copper, oraluminum. Other conductive metals or materials can be used.Alternatively, micro-wires can include cured or sintered metal particlessuch as nickel, tungsten, silver, gold, titanium, or tin or alloys suchas nickel, tungsten, silver, gold, titanium, or tin. Conductive inks canbe used to form micro-wires with pattern-wise deposition or pattern-wiseformation followed by curing steps. Other materials or methods forforming micro-wires, such as curable ink powders including metallicnano-particles, can be employed and are included in the presentinvention.

Electrically conductive micro-wires of the present invention can beoperated by electrically connecting the micro-wires through connectionpads to electrical circuits that provide or receive electrical currentto or from the micro-wires and can control the electrical behavior ofthe micro-wires. In operation, electrically interconnected electricalconductors 50 and electrical components 60 of the present invention areelectrically controlled by a controller. Electrical signals are providedto or received from any electrical components 60 to process information,control sensors, respond to sensors, emit electromagnetic radiation, orrespond to electromagnetic radiation. Integrated circuits and electricalcircuits are generally well known in the computing arts and can includecircuits built on crystalline inorganic materials such as silicon orusing organic materials that are formed on or in or affixed to theflexible substrate 10.

Methods and devices for forming and providing flexible substrates 10 andcoating flexible substrates 10 are known in the photo-lithographic arts.Likewise, tools for laying out electrodes, conductive traces,connectors, and electrical components are known in the electronicsindustry as are methods for manufacturing such electronic systemelements. All of these tools and methods can be usefully employed todesign, implement, construct, and operate the present invention.

The present invention contemplates integrating optical elements 70 withelectrical components 60 and electrical conductors 50. Hence, in anembodiment, a useful method of the present invention includes locatingan electrical component 60 on or in the flexible substrate 10 in thefirst, second, or third portion 21, 22, 23 and folding the flexiblesubstrate 10 so that the optical element 70 directs light to or from theelectrical components 60 or the light-interactive electrical components62.

In one embodiment of the present invention, the optical elements 70, theelectrical components 60, and the electrical conductors 50 are allformed on a common side of the flexible substrate 10, for example firstside 12. As illustrated in FIGS. 3A, 3B, 6, and 7, one or more of theoptical elements 70, electrical components 60, and electrical conductors50 are formed on different sides, for example on first side 12 andsecond side 14. The imprinting method described above is applicable tosuch arrangements. For example, the flexible substrate 10 can include asupport having opposing first and second support sides and a curablelayer coated on both the first and second support sides. One or moremicro-channels are formed in a curable layer on the second support sideand an electrical conductor formed in each micro-channel. A surface ofthe layer on the first support side forms the first side 12 and asurface of the layer on the second support side forms the second side14. Moreover, a useful method can include forming one or more opticalelements 70 in the layer on the second support side in a common stepwith forming the micro-channels on the second support side. Thestructures on the first and second support sides are formed in differentsteps, or alternatively the optical elements 70 and micro-channels inthe curable layer on each of the first and second support sides areformed in a common step with common materials by imprinting the curablelayers on both of the first and second support sides at the same time.

In further steps of the present invention, an additional substrate 16 islocated between the first and second portions 21, 22 in theperpendicular direction 40 or is located between the second and thirdportions 22, 23 in the perpendicular direction 40. The folding steps andlocation of the additional substrate 16 is performed using mechanicalmethods known in the art for manipulating substrates. The folding stepscan include folding the flexible substrate 10 so that the flexiblesubstrate 10 includes the extended portion 26 adjacent to the firstportion 21 with the first portion 21 located between the extendedportion 26 and the second portion 22 in the substrate direction 42. Thefolding steps can also include folding the flexible substrate 10 so thatthe first, second, and third portion 21, 22, 23 are aligned and theoptical elements 70 and electrical components 60 are aligned. A wire 54is electrically connected to one or more of the electrical conductorsusing interconnection methods known in the art.

Referring to FIGS. 13, 14, and 15, and also to FIG. 1A, a method ofmaking a folded micro-wire substrate structure 5 includes providing aflexible substrate 10 in a flexible substrate roll 80 configuration instep 101. The flexible substrate 10 has the first side 12 and the secondside 14 opposed to the first side 12 in the direction 40 perpendicularto the first side 12, the flexible substrate 10 has the first portion21, the second portion 22 adjacent to the first portion 21, and thethird portion 23 adjacent to the second portion 22 so that the secondportion 22 is located between the first and third portions 21, 23 of theflexible substrate 10 (FIG. 1A).

In step 102, the flexible substrate roll 80 is unrolled, and in step 110a plurality of electrical conductors 50 is formed on or in the flexiblesubstrate 10 for example using a material deposition and processor 82 toform the structures described above in the flexible substrate 10 in step110. Optional steps 120, 130, and 150 can also be performed. In oneembodiment of the present invention, the flexible substrate 10 is thenrolled and transported or stored (FIG. 13). In another embodiment, theflexible substrate 10 is not rolled. If the flexible substrate 10 isrolled, it is then unrolled in repeated step 102. In either case, thefirst, second, and third portions 21, 22, 23 are cut with a knife 84from the unrolled flexible substrate 10 to form a cut portion 28 of theflexible substrate 10 in step 155. The cut portion 28 of the flexiblesubstrate 10 is folded in step 160 with the first fold 31 between thefirst and second portions 21, 22 so that the first portion 21 is locatedadjacent to the second portion 22 in the perpendicular direction 40 andwith at least the second fold 32 between the second and third portions22, 23 so that the second side 14 is between the second portion 22 andthe third portion 23 in the perpendicular direction 40 (FIG. 1A) in step160 to form a folded flexible substrate 86. The folded flexiblesubstrate 86 is secured in step 170 to form a secured folded micro-wiresubstrate structure 88 forming the folded micro-wire substrate structure5.

In another embodiment of the present invention, referring again to FIGS.13, 14, and 15, and also to FIG. 2A, a method of making a foldedmicro-wire substrate structure 5 includes providing in step 101 aflexible substrate 10 in a flexible substrate roll 80 configuration. Theflexible substrate 10 has the first side 12 and the second side 14opposed to the first side 12 in the direction 40 perpendicular to thefirst side 12. The flexible substrate 10 has the first portion 21 andthe second portion 22 adjacent to the first portion 21 of the flexiblesubstrate 10 (FIG. 2A).

In step 102, the flexible substrate roll 80 is unrolled, and in step 110a plurality of electrical conductors 50 is formed on or in the flexiblesubstrate 10 for example using a material deposition and processor 82 toform the structures described above in the flexible substrate 10 in step110. In one embodiment of the present invention, the flexible substrate10 is then rolled and transported or stored (FIG. 13). In anotherembodiment, the flexible substrate 10 is not rolled. If the flexiblesubstrate 10 is rolled, it is then unrolled in repeated step 102. Ineither case, the first and second portions 21, 22 are cut with the knife84 from the unrolled flexible substrate 10 to form the cut portion 28 ofthe flexible substrate 10 in step 155. The cut portion 28 of theflexible substrate 10 is then folded in step 160 with a first fold 31between the first and second portions 21, 22 so that the first portion21 is located adjacent to the second portion 22 in the perpendiculardirection 40 (FIG. 2A) in step 160 to form a folded flexible substrate86 (with two portions 21, 22 rather than the three portions 21, 22, 23depicted in FIG. 14). The folded flexible substrate 86 is secured instep 170 to form the secured folded micro-wire substrate structure 88forming the folded micro-wire substrate structure 5.

The invention has been described in detail with particular reference tocertain embodiments thereof, but it will be understood that variationsand modifications can be effected within the spirit and scope of theinvention.

PARTS LIST

-   A cross section line-   5 folded micro-wire substrate structure-   10 flexible substrate-   12 first side-   14 second side-   16 additional substrate-   18 protective layer-   21 first portion-   22 second portion-   23 third portion-   24 fourth portion-   25 fifth portion-   26 extended portion-   28 cut portion-   31 first fold/first fold gap-   32 second fold/second fold gap-   33 third fold-   34 fourth fold-   40 perpendicular direction-   42 substrate direction-   44 light-   50 electrical conductor-   52 electrical connector-   54 wire-   60 electrical component-   62 light-interactive electrical component-   70 optical element/first optical element-   72 second optical element-   74 optical axis-   80 flexible substrate roll-   82 material deposition and processor-   84 knife-   86 folded flexible substrate-   88 secured folded flexible substrate-   100 provide flexible substrate step-   101 provide rolled flexible substrate step-   102 unroll flexible substrate step-   110 form electrical conductors step-   111 coat curable layer on flexible substrate step-   112 imprint curable layer step-   113 cure curable layer step-   114 coat imprinted cured layer with conductive ink step-   115 remove excess conductive ink step-   116 cure conductive ink in micro-channels step-   120 locate electrical components step-   130 coat protective layer step-   140 affix connector step-   150 inspect flexible substrate step-   155 cut flexible substrate step-   160 fold flexible substrate step-   170 secure folded substrate step

1. A method of making a folded micro-wire substrate structure,comprising: providing a transparent flexible substrate having a firstside and a second side opposed to the first side, the flexible substratehaving a first portion and a second portion adjacent to the firstportion of the flexible substrate; forming one or more electricalconductors and one or more electrical components on or in the flexiblesubstrate; forming at least one optical element on or in the flexiblesubstrate in the second portion; and folding the flexible substrate witha first fold between the first and second portions so that the firstportion is aligned with the second portion in a direction perpendicularto the first and second portions of the flexible substrate and theoptical element directs light to or from the electrical component. 2.The method of claim 1 wherein the flexible substrate includes a layer ona side of a support and further including coating a curable layer on theside of the support, imprinting the curable layer to form micro-channelsin the curable layer, and curing the curable layer to form a cured layerhaving micro-channels and a surface, the cured layer forming the layeron the side of the support and a surface of the cured layer opposite thesupport forming the first side.
 3. The method of claim 2 furtherincluding coating the cured layer and micro-channels with a conductiveink, removing the conductive ink from the surface of the cured layer,and curing the conductive ink in the micro-channels to form micro-wiresin the micro-channels that are the electrical conductors.
 4. The methodof claim 2 further including imprinting one or more optical elements inthe curable layer in a common step with imprinting the micro-channels.5. The method of claim 4 further including locating an electricalcomponent on or in the flexible substrate in the first or second portionand folding the flexible substrate so that the optical element directslight to or from the electrical component.
 6. The method of claim 2wherein the side of the support is a first support side and a side ofthe cured layer opposite the first support side is the first side of theflexible substrate, wherein the support has a second support sideopposite the first support side and further including forming one ormore micro-channels in a layer on the second support side and forming anelectrical conductor in each micro-channel, a surface of the layer onthe second support side opposite the second support side forming thesecond side.
 7. The method of claim 6 further including forming one ormore optical elements in the layer on the second support side in acommon step with forming the micro-channels.
 8. The method of claim 1further including printing conductive ink on the flexible substrate andcuring the conductive ink to form the electrical conductors.
 9. Themethod of claim 1 further including forming an electrical component onthe flexible substrate.
 10. The method of claim 1 further includingprinting an electrical component on the flexible substrate.
 11. Themethod of claim 1 further including locating an electrical component onthe flexible substrate wherein the electrical component has a substratedistinct from the flexible substrate.
 12. The method of claim 1 furtherincluding inspecting the flexible substrate and electrical conductorsbefore folding the flexible substrate.
 13. The method of claim 1 furtherincluding locating an additional substrate between the first and secondportions in the perpendicular direction.
 14. The method of claim 1wherein at least one electrical conductor extends from the first portionto the second portion and across the first fold.
 15. The method of claim1 further including forming a protective layer on the first side of theflexible substrate so that the electrical conductors are between theprotective layer and at least a portion of the flexible substrate. 16.The method of claim 1 wherein the flexible substrate further includes anextended portion adjacent to the first portion so that the first portionis located between the extended portion and the second portion andfurther including electrically connecting a wire to one or more of theelectrical conductors.
 17. The method of claim 1 further includingforming an electrical connection between an electrical conductor in thefirst portion and an electrical conductor in the second portion thatdoes not extend across the first fold.
 18. A method of making a foldedmicro-wire substrate structure, comprising: providing a flexiblesubstrate in a rolled configuration, the flexible substrate having afirst side and a second side opposed to the first side, the flexiblesubstrate having a first portion, a second portion adjacent to the firstportion of the flexible substrate; unrolling the flexible substrate andforming a plurality of electrical conductors on or in the flexiblesubstrate; cutting the first and second portions from the unrolledflexible substrate to form a cut portion of the flexible substrate;folding the cut portion of the flexible substrate with a first foldbetween the first and second portions so that the first portion islocated adjacent to the second portion in the perpendicular direction ina direction perpendicular to the first and second portions of theflexible substrate; and securing the folded flexible substrate to formthe folded micro-wire substrate structure.
 19. A method of making amicro-wire substrate structure, comprising: providing a transparentflexible substrate having a first side and a second side opposed to thefirst side, the flexible substrate having a first portion and a secondportion adjacent to the first portion of the flexible substrateseparated from the first portion by a first fold gap; forming at leastone optical element on or in the flexible substrate in the secondportion; and forming one or more electrical conductors on or in theflexible substrate in the first portion.